From e2f2bbe208b4c7ebcedacfc8333df1e52cbf07eb Mon Sep 17 00:00:00 2001
From: Taylor Beebe <taylor.d.beebe@gmail.com>
Date: Mon, 20 Nov 2023 12:07:29 -0800
Subject: MdeModulePkg: Fix MAT SplitRecord() Logic

SplitRecord() does not handle the case where a memory descriptor
describes an image region plus extra pages before or after the
image region. This patch fixes this case by carving off the
unrelated regions into their own descriptors.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Dandan Bi <dandan.bi@intel.com>
Signed-off-by: Taylor Beebe <taylor.d.beebe@gmail.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
---
 .../ImagePropertiesRecordLib.c                     | 56 +++++++++++-----------
 1 file changed, 27 insertions(+), 29 deletions(-)

(limited to 'MdeModulePkg/Library')

diff --git a/MdeModulePkg/Library/ImagePropertiesRecordLib/ImagePropertiesRecordLib.c b/MdeModulePkg/Library/ImagePropertiesRecordLib/ImagePropertiesRecordLib.c
index 7c0ecd07c1..9d4082280b 100644
--- a/MdeModulePkg/Library/ImagePropertiesRecordLib/ImagePropertiesRecordLib.c
+++ b/MdeModulePkg/Library/ImagePropertiesRecordLib/ImagePropertiesRecordLib.c
@@ -323,7 +323,6 @@ SplitRecord (
   UINT64                   PhysicalEnd;
   UINTN                    NewRecordCount;
   UINTN                    TotalNewRecordCount;
-  BOOLEAN                  IsLastRecordData;
 
   if (MaxSplitRecordCount == 0) {
     CopyMem (NewRecord, OldRecord, DescriptorSize);
@@ -344,35 +343,16 @@ SplitRecord (
     NewImageRecord = GetImageRecordByAddress (PhysicalStart, PhysicalEnd - PhysicalStart, ImageRecordList);
     if (NewImageRecord == NULL) {
       //
-      // No more image covered by this range, stop
+      // No more images cover this range, check if we've reached the end of the old descriptor. If not,
+      // add the remaining range to the new descriptor list.
       //
-      if ((PhysicalEnd > PhysicalStart) && (ImageRecord != NULL)) {
-        //
-        // If this is still address in this record, need record.
-        //
-        NewRecord        = PREVIOUS_MEMORY_DESCRIPTOR (NewRecord, DescriptorSize);
-        IsLastRecordData = FALSE;
-        if ((NewRecord->Attribute & EFI_MEMORY_XP) != 0) {
-          IsLastRecordData = TRUE;
-        }
-
-        if (IsLastRecordData) {
-          //
-          // Last record is DATA, just merge it.
-          //
-          NewRecord->NumberOfPages = EfiSizeToPages (PhysicalEnd - NewRecord->PhysicalStart);
-        } else {
-          //
-          // Last record is CODE, create a new DATA entry.
-          //
-          NewRecord                = NEXT_MEMORY_DESCRIPTOR (NewRecord, DescriptorSize);
-          NewRecord->Type          = TempRecord.Type;
-          NewRecord->PhysicalStart = TempRecord.PhysicalStart;
-          NewRecord->VirtualStart  = 0;
-          NewRecord->NumberOfPages = TempRecord.NumberOfPages;
-          NewRecord->Attribute     = TempRecord.Attribute | EFI_MEMORY_XP;
-          TotalNewRecordCount++;
-        }
+      if (PhysicalEnd > PhysicalStart) {
+        NewRecord->Type          = TempRecord.Type;
+        NewRecord->PhysicalStart = PhysicalStart;
+        NewRecord->VirtualStart  = 0;
+        NewRecord->NumberOfPages = EfiSizeToPages (PhysicalEnd - PhysicalStart);
+        NewRecord->Attribute     = TempRecord.Attribute;
+        TotalNewRecordCount++;
       }
 
       break;
@@ -380,6 +360,24 @@ SplitRecord (
 
     ImageRecord = NewImageRecord;
 
+    //
+    // Update PhysicalStart to exclude the portion before the image buffer
+    //
+    if (TempRecord.PhysicalStart < ImageRecord->ImageBase) {
+      NewRecord->Type          = TempRecord.Type;
+      NewRecord->PhysicalStart = TempRecord.PhysicalStart;
+      NewRecord->VirtualStart  = 0;
+      NewRecord->NumberOfPages = EfiSizeToPages (ImageRecord->ImageBase - TempRecord.PhysicalStart);
+      NewRecord->Attribute     = TempRecord.Attribute;
+      TotalNewRecordCount++;
+
+      PhysicalStart            = ImageRecord->ImageBase;
+      TempRecord.PhysicalStart = PhysicalStart;
+      TempRecord.NumberOfPages = EfiSizeToPages (PhysicalEnd - PhysicalStart);
+
+      NewRecord = (EFI_MEMORY_DESCRIPTOR *)((UINT8 *)NewRecord + DescriptorSize);
+    }
+
     //
     // Set new record
     //
-- 
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